WS2259
Features
■ Burst Mode function
■ Low startup current (4uA)
■ Low operation current (1.7mA)
■ Built in Leading edge blanking (LEB)
■ Built in Synchronous slope compensation
■ Current mode operates
■ External programmable switching frequency
■ Cycle by cycle Over Current Protection
■ over temperature protection(OTP）
■ Soft-start
■ VDD over voltage protection and clamp
■ under voltage lockout with hysteresis(UVLO）
■ Driver Output clamped(13V)
■ Soft-driver function for lower EMI
■ Frequency jitter
■ Constant output power limited
■ Over load protection(OLP)
■ Free audio noise operation
General Description
WS2259 which is optimized for high performance is a
highly integrated current mode PWM control IC. It is applied
for switch power of the small-sized and medium-sized for
example the power adaptor. For lower the standby power and
higher RoHS compliant, the IC has the Burst Mode function
and very low startup current and working current. At the
condition of no load or light load, the IC operates in extended
‘burst mode’ to minimize switching loss by lower the switching
frequency. The low startup current and low operating current
contribute to a reliable power on startup design with WS2259.
A large value resistor could thus be used in the startup circuit
to minimize the power consumption and improve the efficiency
of the power convert.
The internal synchronous slope compensation circuit
improves system large signal stability and reduces the
possible subharmonic oscillation at high PWM duty cycle
output. Leading-edge blanking on current sense(SENSE)
input removes the signal glitch due to snubber circuit diode
reverse recovery and thus greatly reduces the external
component count and system cost in the design.
WS2259 offers complete protection coverage with
automatic self-recovery feature including cycle by cycle over
current protection (OCP), over load protection (OLP), over
temperature protection (OTP), VDD Over Voltage Protection,
under voltage lockout (UVLO). The gate-driven output is
clamped to maximum 13V to protect the external MOSFET.
Excellent EMI performance is achieved by using the frequency
jitter and the soft-switching at the totem pole gate drive output.
The tone energy at below 20KHZ is minimized in the design
and audio noise is eliminated during operation. The IC can be
used as the best alternative products of the linear power
supply or the RCC-mode power to improve the whole
performance of the switch power system and lower the cost.
WS2259 is offered in SOT23-6, SOP-8 and DIP-8 packages.
Applications
Universal switch power supply and offline AC/DC
flyback converter:
■ Battery Charger
■ Power Adaptor
■ Set-Top Box Power Supplies
■ Open-frame SMPS
Typical Application Circuit
Rev.A Apr.2011
Copyright@Winsemi Microelectronics Co., Ltd., All right reserved.
WS2259
Recommended Operating Condition
Symbol
VDD
RI
T
A
Parameter
VDD Supply Voltage
RI Resistor
Operating temperature
Value
10~30
100
-20~85
Unit
V
Kohm
℃
Absolute Maximum Ratings ( Note 1)
Symbol
VDD
V
FB
V
SENSE
V
RI
T
J
T
STG
V
CV
I
CC
Parameter
DC Power Supply
FB input voltage
SENSE input voltage
RI input voltage
Operation Junction Temperature
Storage Temperature
Vcc Clamp Voltage
Vcc Clamp Continuous Current
Value
30
-0.3~7
-0.3~7
-0.3~7
-20~150
-40~150
31
10
Unit
V
V
V
V
℃
℃
V
mA
Note 1
: Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device.
These are stress ratings only, functional operation of the device at these or any other conditions beyond those indicated in
the Recommended Operating Conditions section are not implied. Exposure to absolute maximum-rated conditions for
extended periods may affect device reliability.
ESD Information
Symbol
V
ESD-HBM
V
ESD-MM
Parameter
Human body model on all pins
Machine model on all pins
Value
3
300
Unit
KV
V
4/11
Steady, keep you advance
WS2259
Electrical Characteristics
(T
A
=25℃，VCC=16V, if not otherwise noted)
Supply Voltage (VDD)
Parameter
Operation voltage
Turn on threshold Voltage
Turn-off threshold Voltage
Start up current
Operation Current
Symbol
VDD_OP
UVLO_ON
UVLO_OFF
I_VDD_ST
I_VDD_OP
Test condition
Min
6.8
13.5
Typ
7.5
14.5
4
1.7
Max
30
8
15.5
10
2.3
Unit
V
V
V
uA
mA
V
V
VDD=13V,RI=100K
VDD=16V,RI=100K,V
FB
=3V
GATE with 1nF to GND
VDD_OVP
VDD Zener Clamp Voltage
VDD_Clamp
IVDD=10mA
29
31
Feedback Input Section
V
FB
Open Loop Voltage
FB Pin Short Current
Power limiting FB Threshold
Power limiting Debounce
Input Impedance
Maximum duty cycle
V
FB
_Open
I
FB
_Short
V
TH
_PL
T
D
_PL
Z
FB
_IN
Max_Duty
VDD=16V,FB open,
FB Shorted to GND
VDD=16V, RI=100K
VDD=16V,FB open,RI=100KΩ
VDD=16V,FB=2V/3V,CS open
VDD=16V,FB open,
CS=0,RI=100KΩ
5.4
0.3
3.2
48
11.5
72
5.9
0.45
3.65
60
14.5
77
6.4
0.6
4.0
72
18
82
V
mA
V
ms
kΩ
%
Current Sense Section
Leading edge Blanking Time
OCP control delay
OCP threshold
TLEB
T
D
_OC
T
TH
_OC
GATE with 1nF to GND
FB＝3.2V
0.68
330
70
0.78
0.78
ns
ns
V
Oscillator Section
Frequency
Fosc
Jitter period
Jitter range
Burst mode frequency
Frequency variation versus temp. Deviation
Frequency variation versus VDD
Fosc_BM
∆f_temp
∆f_VDD
VDD=9.5V,RI=100K, FB=1V
TEMP = -20 to 85℃
VDD = 12 to 25V
VDD=16V,RI=100K,,FB=3.2V
For 65K
60
65
4
±5
22
5
5
70
khz
ms
%
khz
%
%
RI Section
RI voltage
V
RI
VDD=16V,RI=100KΩ,CS=1V
1.94
2
2.06
V
Thermal protection
Thermal shutdown temperature
T_shutdown
150
℃
GATE Output Section
Output voltage Low
Output voltage high
Output clamp voltage
Rising time
Falling time
VOL
VOH
VClamp
Tr
Tf
VDD = 16V, Io = -20mA
VDD = 16V, Io = 20mA
VDD = 20V
VDD = 16V, GATE with 1nF to GND
VDD = 16V, GATE with 1nF to GND
9
11
13
250
75
14.5
0.8
V
V
V
ns
ns
5/11
Steady, keep you advance
Embedded System
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